Learn Farsi: خدمه‌ی مضطرب در حال آماده کردن اژدرهای سنگین تهاجمی هستند. - The anxious crew is preparing the heavy attack torpedoes.

This is a strict rule in chained Ezafe constructions. When a noun has multiple modifiers, qualitative adjectives describing physical traits like سنگین (heavy) must come before relational or classifying adjectives that describe category or function, like تهاجمی (attack/offensive). Therefore, 'heavy attack torpedoes' translates to اژدرهایِ سنگینِ تهاجمی.

How does the progressive structure در حال work with the compound verb آماده کردن here?

The phrase در حال (in the state of) is followed by the full infinitive of the verb to create a continuous meaning. For compound verbs like آماده کردن (to prepare), you keep the compound together as a single noun phrase. Notice that the object of the action comes after the infinitive, connected by an unseen Ezafe: در حال آماده کردنِ اژدرها (literally 'in the state of the preparing of the torpedoes').

Since خدمه (crew) is singular in form, why is the verb هستند (they are) plural?

While خدمه is grammatically a collective noun, Farsi commonly uses plural verbs for collective nouns that refer to groups of people, like a crew, team, or family. This is especially true when the sentence highlights the individuals' feelings or actions, such as being مضطرب (anxious) and actively preparing weapons.

Is there an Ezafe between خدمه and مضطرب? Why is there a ی at the end of خدمه‌ی?